Ring-back arrangement for common-battery telephone party-lines.



F. LUBBERGER.

RINGBACK ARRANGEMENT FOR COMMON BATTERY TELEPHONE PARTY LINES.

APPLICATION FILED SEPT. 19. 1907- RENEWED FEB. 23, 1918. 1,280,783.

Patented Oct. 8, 1918.

3 HEETS-SHEET I A ffmvz 8W F. LUBBERGER.

RING BACK ARRANGEMENT FOR COMMON BATTERY TELEPHONE PARTY LINES.

APPLICATION FILE'D SEPT. 19. 1907- RENEWED FEB. 23,1918. 1,280,783.

Patented Oct. 8, 1918.

3 SHEETS-SHEET 2 *1IIIIIIlIIIHIh A KF. LUBBERGER. RTNG BACK ARRANGEMENTFOR COMMON BATTERY TELEPHONE PARTY LINES. APPLICATION FILED SEPT. 9.1907: RENEWED FEB. 23, I9I8.

1,280,? 83. Patented 001;. 8, 1918',

3 SHEETS-SHEET 3.

\I 0; g\ Q o QQQ kl h N {353R Q M 3 ggkR 3 A v we WE s m R {BE g U I EDsra'ras PATENT 'UFFICE.

rnrrz LUIBBERGER, or oHIcAeoJLLnvoIs, ASSIGNOR, BY Muslin ASSIGNMENTS, T

AUTOMATIC ELECTRIC COMPANY, A CORPORATION or ILLINOIS.

RING-BA CK AERANGEMENT FOR COMMON-BATTERY TELEPHONE PARTY-LINES.

' Specification of Letters Patent.

Patented Oct. 8, 1918.

Application filed September 19, 1907, Serial No. 393,654. RenewedFebruary 23, 1918. Serial No. 218,899.

. have invented a certain new and useful Improvement inRing-BackArrangements for Common-Battery Telephone Party Lines, of

which the following is'a specification.

My invention relates to automatic partyline telephone systems ingeneral, but more particularly to the non-lnterfering andintercommunicating party-line system dis closed in my nor. applicationSerial No.

. 393,653,' filed ept. 19, 1907, as will herein-.

after morefully appear.

Objects of my invention are to provide a party-line system of thischaracter in which same line is adapted to control the {low of talkingcurrent to the subscrlbers l1ne, as

"the electrical current for. talking purposes is supplied from theexchange or central station; in which the special ring-back arrangement'for use between subscribers onthe well as to control the trunk-releasecircuit through the first-selector or other switch; in which the linecircuit is controlled by a relay common to all of the subscribers onaparty-line, which relay is energized by battery current flowing over oneside ofthe' line when an subscriber presses his rin ng-key, the win 'n"or coils of said relay. ein included in 51 is common to the difierentsubstations, there- 'by preventing the release of the apparatus at theexchange which would otherwise take place should the called subscriberhappen to] answer before the line is grounded the last time at thecallin substation; and i'n'which certain details an features ofimprovement and novel combinations are employed for in- -To. theforegoing and'other useful ends,

my invention consists in matters hereinafter Gt fOIth and claimed. 9, v

In the accompanying drawings Figure '1 is a diagram showing an'autornaticparty line system embodying the principles of my invention,in which central ener is used for talkin and signaling. It willbe seenthat the su stations A, A and A are allot:

ted to the party-linethat terminateslat the central oifice in thefirst-selector switch C,

which latter may be of the general'type disclosed in United StatesPatent No. 815,321,

e connection to ground w ich general efiiciency and service-l subscrlberafter havlng properl granted March 13, 1906, to Keith, Erickson andErickson, having rotary and non-rotary movements. At 1) is shown anarrangement by means of which any subscriber of the party-line may ringback upon his own line.

A central battery for talking and operating purposes is shown at Bhaving its positive terminal referably grounded at Gr, and a centralringer generator for signaling is shown at E.

ferent lines. -The substation .A is similar to substationsA, A and Aand, as shown, is'allotted to the first-selectorswitch H.

. It will be understood that in the central 'oifice, in addition to thefirst-selector; switches allotted to the subscribers, lines, 'there maybe second-selector switches of the same general type, and connectors ofthe general type shown in United States Patent No. 815,1 6, grantedMarch 13, 1906, to

Keith, Erickson andiErickson, by means of which the subscribers mayestablish connecthis purpose the various bank levels of the switches maybe and are provided with trunk-lines leading" to second -selector ,tionwith lines other than their own. For

switches, and likewise from thesecond-selecj tor'bank levels withtrunk-lines leading to the connector switches, as is customary. With mynew system one level, either in the the trunk-lines from the contacts insome certain level, instead of leading to a' selector or connectorswitch, lead to a ring-back arrangement, as shown at D in Fig. 1; and aoperated the central office switch or switc es and es tablishedconnection with said ring-back 'level, may then cause ringing current topass back over his line to signal-some other I subscriber occupying thesame line with him. j In Fig. 1 this ring-back arrangement is shownallotted to the second level of the first-selector banks. either of thefirst or second selector banks,

Any level, however,

may be e uipped in the same manner.

first or second selector bank,'is allotted to the signaling device, asshown at D-that is,

, The su stations may be of any suitable or approved type. The ones inconnection with which I have elected to illustrate my invention comprisethe receiver 2, a switch- 1100113, which is provided with cam-armsswitch-hook is down the cam-arm 6 carries the spring 14 out ofengagement with the spring 15, by which the substation ground G is cutoil. When the switch-hook is up, however, the 'cam-arm 7 presses thesprings l6 and 17 into contact, whereby the transthe side switch is innormal or first posimitter 18 in series" with the primary winding 19 ofthe induction-coil 20 is bridged across the main line conductors. Thesecondary winding 21 is included in a series circuit with the'receiver2. The calling device, as shown, comprises two push-buttons 22 and 23which, when pressed, are adapted to carry the springs'24 and 25 out ofengagement with the contact points 26 and 27 and into engagement withthe ground post 28. The signaling deviceby means of which the subscribermay ground the vertical line conductor to signal a called subscribercomprises a push-button 29 which, when pressed, carries the spring 30out of engagement with the spring 31 and into engagement with thecontact point 32. Allotted to the main line conductors 33 and 34, whichare common to the substations A, A A etc., there is a relay 35 composedof two windings 36 and 37. The winding 36 may be of comparatively highresistance, while the winding 37 is comparatively low. This relay, uponenergizing, operates to disengage the springs 38 and 39 and to carry thesprings 40 and 41 into contact. When the springs 38 and 39 disengage,then the rotary line conductor 34 is disconnected from the substation.The'engagement of the springs 40 and 41 provides a shunt orshort-circuit for the winding 36.

The first-selector switch shown at. C is constructed as follows Theswitch shaft (not shown) carries the vertical and rotary wipers 45 and46, respectively, and the private wiper 47. The side switch is wellknown and comprises the side switch wipers '48, 49, and 51, which may bedesignated as the vertical, rotary and private side switch wipers, andthe rotary magnet wiper, respectively. The side switch is under thecon'trolof the private magnet 52, and when tion the wipers 48, 49, 50and 51 occupy the contact points 53, 54, 55 and 56, respectively. In thesecond position the wipers rest on the contact points 57, 58, 59 and 60,respectively, and in the third position the contact points 61, 62, 63and 64 are engaged by their tion, is energized. .The vertical and rotaryline relays 65 an'd67, acting conjointly, pro- Videmeans whereby thesubscriber controls the release magnet 69 while the side switch is inthe first or second position. If the sideswitch 1 passes to the thirdposition, --then, since the selector is of the trunk-release type, theselector is controlled by means of the back-release relay 70 from thenext switch with which a connection is at that time established, throughthe private wiper I 47. The bridge-cut-off relay '71 is provided to openthe connection between the line relays 65 and 67, and between saidrelays and battery B. This is desirable, because if the relays are notdisconnected from each other and battery the ringing current forsignaling the subscriber may 0 erate either or both of the relays'65 and6, and cause some I interference with the switch. It is also desirableto remove the bridge formed through the said relays from across the lineto give the voice-currents as clear a path as possible. In addition, thefirstselector is provided with a normal arm 72 which, when the shaft israised, permits the spring 7 3 to pass out of engagement with t e spring74 and into engagement-with the spring 75. The normal conductors '76, 77and 78, over which'incoming calls are made, terminate inthe connectorbanks, as' is usually the case in systems of this general character. a

The ring-back arrangement shown at. D comprises the vertical and rotaryline relays 79 and 80 connected in series with the windings 81 and 82'of the difi'erential relay 83',- and tothe battery terminals. A deadresist-- ance coil 84 is provided in the trunk-release circuit to cutdown the flow of current through the release relay 70 of the selector,which relay is of one-half ohm resistance. The ringer relay 85, uponenergizing, operates to bridgethe terminals of the ringer generator Eacross the line conductors. The condensers 86 and 87 are provided forbridging the impedance in the vertical and rotary line talking circuits.

The connector switch may also be of any suitable or approved type, forinstance of the general type described in said connector patent. Themechanical details ofthe selector and connector, as is well known, are

7 very much the same, although there is some material difference in theclrcuits. For instance, the connector switch shaft (not .shown), likethe selector switch shaft, carrice the line wipers 124 and 125 and theprivate wiper 126. The connector switch is also controlled by thecalling subscriber through the medium of the vertical and rotary linerelays 127 and 128. The vertical line relay 127 directlycontrols thevertical.

magnet 129 and also the rotary magnet 130. The function of the verticalmagnet 129 is to give the shaft and shaft wipers a vertical motion, andthe rotary magnet 130 imparts to the shaft and shaft wipers a rotary orcircular motion. The rotary line relay 128 controls the private magnet131, whichlatter, under certain conditions, controls in turn thevertical and rotary magnets 129 and 130, the release magnet .132, andalso the side switch wipers 134, 135, 136 and 137. The side switch ofthe connector, like the I side switch of the selector, has a normal orfirst osition, a second position and a third means of the vertical linerelay 127, to con-' trol the ringer relay 144 by means of "which theringer generator E is bridged across the. terminals of the called lineto signal the called subscriber. The back-bridge relay 143, comprisingthe windings1145 and 146,

rovides the called subscriber with talking battery current when theprimary circuit of the called substation is bridged across the line. Thecentral station is equipped with the busy-signaling apparatus I of any,suitable design, as, for example, the one comprising an interrupter 147in series with the primary winding 148 of the induction-coil 149,whereby a busy-signaling current is in-' duced in the secondary winding150 of the said induction-coil. Thesecondary winding 150 is connectedwith the side switch wiper 135 through the normal springsl51 and 152when the switch shaft is raised and the side switch is in firstposition.

A clearer understanding of my invention may be had by considering itsaction when one subscriber operates the central office switches to callback on his own line.

lit will be assumed that subscriber A desires to signal the subscriberat substation A, in which event the selector switch to the lineconductors 33 and 34 o allotted arrangement D which is allotted to thesecond level of the first-selector banks. The subscriber at substation Aremoves the receiver 2 from the switch-hook 3, whereby the springs 14and 15 engage, thus providing ground for the.ground post 28. Since thering-back arrangement is allotted to the second level of thefirst-selector, the vertical line conductor 33 is given two groundimpulses and the rotary line conductor 34 is given one. The push-button22 is, therefore, pressed twice, whereby the spring 24 is carried ontothe ground post 28 twice, and as a result the vertical line relay 65 ofthe firstselector C is energized each time by a flow of current from thesubtation ground Gr through the springs 14 and 15, ground post 28,spring 24, vertlcal line conductor 33, side switch wiper 48 and contactpoint 53,

throu h the vertical line relay 65, bridgecut-o relay springs 88 and 89to the battery lead 90, thence through battery B to ground G. Thevertical line relay, upon energizing, operates to place the line relaysprings 91 and 92 in contact, thus in turn closing an energizing circuitthrough the vertical magnet 66. The vertical magnet is therebyenergized, and the wipers 45, 46 and 47 of the l selector 0 are raisedto the second bank level and brought opposite the first contact.

The energizing circuit for the said vertical magnet 66 extends fromground Gr through the springs 91 and 92, private magnet springs 93 and94, through the vertical ma net 66 to the battery lead 90, thence througbattery B to ground G. The rotary pushbutton 23 is thenpressed, carryingthe spring 25 onto the ground post 28, thereby establishingan energizingcircuit throu h the rotary line relay 67 extending from t e substationground G to the round post 28, spring 25,'through the springs 38 and 39,rotary line conductor 34, side switch wiper 49, contact point 54,through the winding of the rotary lme why 67, bridge-cut-ofi' relaysprings 95, 88 and 89 to the battery lead 90, thence through battery Bto ground G.

The rotary line relay, upon energizing, presses the springs 96 and 91into contact, thereby establishing a circuit through the private magnet52 extending from ground G? through the springs 91 and 96, privatemagnet 52 to the battery lead 90, thence through battery B to ground G.The private magnet, upon energizing and deenergizing, permits theselector side switch to pass from first to second position, permitj tingthe side switch wipers 50 and 51 to engage the contact points 59 and 60.The closure of connection between the side switch wiper 51 andthecontact oint 60 provides an energizing circuit for t e rotary magnet68 extending from ground G to the side I is operated switch 51,interrupter springs 97, through to establish connection with thering-back the winding of the rotary magnet 68 to the thence throughbattery Bto ground G. The

battery lead 90, thence throughbattery B to ground G. The said rotarymagnet 68 .then operates to rotate the Wipers 45, 46

and 47 into engagement with the first c0ntact of the second level, fromwhich contact, it is assumed, the trunk-line conductors 98, 99 and 100lead to the ring-back arrangement D. If the first trunk-line is busy,however, and the wipers have to pass over busy contacts, then as soon asthe private wiper 47 engages the first grounded private bank contactpoint the private magnet 52 again energizes, locking the side switch insecond position. The energizin circuit for the said private magnet extens from ground. G through an occupyin switch .(not shown) to the privatewiper 4 thence over the conductor 101, through the back-release relay70, side switch wiper '50,contact point 59,

private magnet 52 to the battery lead 90,

private magnet 52, when 'thus energized, locks the side switch in secondposition, and

"the wiper 51 in engagement with the contact point 60, whereby therotary magnet 68 will be energized step-by-step until the wipers arecarried beyond the last busy trunk-line.

At the instant thatthe private wiper leaves I the last busy contactpoint the energizing switch passes to third position. If, however,

circuit through the private magnet 52is destroyed, and asa result theselector side there are no busy trunk lines the rotary magnet 68releases the side switch to third position as soon as the wipers arecarried into engagement with the first trunk-line. As soon as the sideswitch passes to third position, as stated, the subscribersline-conductors 33 and 34 are extended to the conductors 98 and99'which, inthis case, it is assumed lead to the ring-back arrangementD. The extending of the line occurs, of course, as soon as the sideswitch wipers 48 and 49 engage the contact points 61 and 62,respectively. Not only is the subscribers line thus extended, but aguarding potential is seizure by other su scribers. It will be seen,

of course, that the energizing circuit for the rotary magnet 68, towhich reference has already been made, is destroyed when the idletrunk-line is seized-that is, when the sequence.

side switch wiper 51 leaves the contact point- 60. The callingsubscriber has new extended the conductors 33 and 34"to the ring-backarrangement shown at'D, and the central oflice switches occupy theposition indicated in Fig. 1. To signal the subscriber at substation Athe calling subscriber at substa'v tion A presses the signaling button29,. whereby an energizing circuit is established through the verticalrelay of the ring-back through the windings 36 and 37 of the iarrangement, extending from ground G double-wound relay 35, conductor102,'contact point 32, push-button spring 30, through thesprings 17 and16, through the calling device springs to the vertical line con- .ductor33, through the side switch-wiper 48, shaft wiper 45, trunk-lineconductor 98, vertical line relay 79, winding 81 ofthe differentialrelay 83 to the battery lead 90, thence through battery B to ground G.This circuit provides energizing current for the, relay 35, whichoperates to disengage the springs 38 and 39 and to close the springs 40and 41 in contact. When the springs 40 and 41 engage, a new circuit isestablished, shunting orshort circuiting the high resistance winding 36.Thisnew circuit is the same as the old' 'circuit, except that the highresist ance winding 36 is shunted or short-circuited. The winding 37 isprovided in order to maintain the relay 36 energized after the winding36 is 'short-circuited. When. the winding 36-is included in series inthe circuit, sufiicient current doesnot fl'ow to oprelay operates,sufficient current then flows 'eratively energize the relay 7 9; butwhen't .this winding 36 is short-circuited, after the to operativelyenergize the vertical line'relay 79; and also,.since the winding 81 isincluded in this circuit, the relay 83 operates,.

but this operation at this time is-of no .con-

The relay 79, upon energizln'g, closes the springs 103 and 104 incontact,

" whereby an energizing circuit is established through the ringer relay85, extending from" ground G atlthe selector C, through the Y sideswitch wiper 50, back-release relay .70

to-the private wiper 47, conductor 100,

through the springs 105 and 106, through the ringer relay 85, springs104 and 103, through the dead resistance coil 84 to the battery lead 90,thence through battery B to' ground G. Theringerrelay 85, upon ener--gizing, operates to shift the spring 107 from the spring 108 to thespring 109; also, the spring 110 is carried intov'engagement with thespring 111. By the operation of this relay the terminals of the ringergenerator E are bridged across the extended line conductors 33 and 34,.whereby ringing current .is permitted to flow from the rotarylineconductor 34 to the conductor 113, and then 7 I through the ringers 114and 115 in multiple with the substations A and A to the vertitary lineconductor 34,. if the calling subscriber presses his signaling buttonafter the called subscriber has removed hlS receiver from theswitch-hook, and then to the rotary line relay 80 of the ring-backarrangement,

thus energizing both the vertical and rotary line relays simultaneously,whereby the re lease of the central office apparatus would be broughtabout. To prevent the possibility of a premature releasebeing broughtabout in this manner, the relay is providedfor opening up the rotaryline conductors, and thus preventing the ground potential at thevertical line conductor from passing through a subscribers station tothe rotary line conductors. The subscriber at substation A, in responseto his signal, which may be two rings, removes his receiver from theswitch-hook and bridges his primary circuit across the main lineconductors 33 and 34, in multiple with the primary circuit of thesubstation A. Talking battery current for these two multiple primarycircuits is established over a circuit extending from ground Gr throughthe springs 118 and 119, through the winding 82 of the relay 83, ro-

' tary line relay 80, ringer relay springs 108 and 107, through theconductors 99 and 34, springs 39 and 38, then through the primarywindings 20 and 17, transmitters 18 and 116 to the vertical lineconductor 33, side switch wiper 48, shaft wiper 45, conductor 98,

through the vertical line relay 79 and wind ing 81 of the differentialrelay 83 to the battery lead 90, thence through battery B to ground G.The windings 81 and 82 of the relay 83 are so arranged that when .bothwindings carry current, as before explained, the said relay does .notoperatively energize; also, the relays 79 and 80, which are included inthe talking circuit, are so arranged and adjusted that they do notoperate when included in the talking circuit. The two substations beingthus provided with talking current, conversation may be carried on inthe well-known manner. After the subscribers have finished theirconversation the subscriber who first restores his receiver to theswitch-hook brings about the release of the central ofiice switchingapparatus, as follows: Suppose subscriber A restores his receiver first.In that event the cam-arm 4 presses the release springs 7., 8 and 9 intoassists the winding 81 in maintaining the relay 83 in an operatedposition. The energizing circuits through the windings 81 and 82 extendsfrom the substation ground G through the springs '14 and 15, through therelease springs 7, 8 and .9 to the vertical and rotary line conductors33 and 34, then on one side over the vertical line conductor to the sideswitch-wiper 48, shaft wiper 45, trunk conductor 98, through thevertical relay 79 and winding 81 to the battery lead 90, thence throughbattery B to ground G; and on the other side the circuit over the rotaryline extends from the conductor 34, through the side switch wiper 49,shaft wiper 46, conductor 99,through the ringer springs 107 and 108,through the rotary relay 80 and winding 82, through the springs 119 and120 to the battery lead 90, thence through battery B to ground G. Thevertical and rotary line relays 79 and 80 now operatively energize toplace the springs 103, 104 and '47, conductor 100, springs 105, 104 and103,

resistance coil 84 to the battery lead 90, thence through battery B toground G. The back-release relay 70, upon energizing, places the springs122 and 123 in. contact, whereby an energizing circuit is in turnprovided for the release magnet 69, this circuit extending from groundGr through the springs 122 and 123, and through the release magnet 69 tothe battery lead 90, thence through batteryB to ground G. All of therelays and magnets thus energized attract their respective armatures andremain in readiness to return to normal position as soon as the groundto the main line conductors is broken, when the release springs 7, 8 and9 disengage. v If the subscriber at substation A, however, desires toestablish connection with a subscriber on some other line, the selectorC is operated to seize some idle trunk-line leading to a connector, orto another selector, and finally to a connector which is operated toestablish connection directly with the desired line. For example: Tocall the number 320 (substation, A the subscriber at substation Aremoves his receiver from the switch-hook and operates the callingknownmanner. When the device is operated for thefirst digit thefirst-selector switch is operated to establish connection with an'idletrunk-line leading to the connector switchF. The impulses for the lasttwo digits are directed toward the connector responding tothedesiredline. The first the vertical line relay 65 of the first-selector:

j the vertical line relay v 90, as previously, explained The verticallinerelay in turn'op'erates to energize the before, and the privatemagnet in turn op;

side switch: frdm. first to whereby the rotary magnet becomes energizedand, the shaft wipers 45, 46 and 47 are operated to sele'ct anlidle' .C.is energized-each time 'by a flow of cure substation ground. through.

rent from i t 65 to the battery lead vertical magnet 66,, whereby theshaft wipers are raised opposite the bank contaets of the third level.Following the vertical impulses the rotary line relay 67 is energized'aserates to carry the second positlon,

trunk-line leading to the connectpr switch F. The grounding of thelineconductors 33' and 34 for the last two digits affects the connector byoperating the vertical and rotary line relays 127 and 128.. When thevertical line conductor 33 is grounded the-vertical.

' vertical line conductor shaft wiper 45, trunk conductor 153, ver-' 1line relay 127 is energized .by aflow of currentfromsubstation ground Gthrough the.

33, side switch wiper 48, tical. line relay 127 winding 141 of the relay140 to the battery lead 90-, thence through 1 third position a guardingpotential is estabbattery B to ground G. The winding-141 of the relay140 being included in this circuit but this operation is the said relayenergizes,

. Each without effect at this particular time.-

time that the vertical line relay 127 operates for the second digit thevertical magnet 129 energizes to carryv the shaft operatively 125 and126 in a vertical direcwipers 124,

" .tion 'one step at a time until the said wipers are carried two stepsand. thus brought op-i .posite a level nals of the line #320. Thecircuit through in which are located the termi the vertical magnet 129extends from ground G through the springs154 and 155, private magnetsprings wiper 136, vert cal magnet 129 to the battery lead 90, thencethrough battery B to ground When the rotary line conductor 234 isvertical line conductor, the connector rotary grounded, following thegrounding of i'the line relay 128'becomes energized through a circuitfrom ground G to the rotary line I conductor 34, side switch wiper 49,shaft wiper 46, rotary trunk conductor 158, rotary line re- 1 lay 128,winding 142 of the difierential relay device once for each digit inthewell 3 the spring 26 is'pressed onto Asa result" lay operates,

shaft wipers 124 and. 125

156 and 157, side switch memes batterylead ound G.

90, thence through battery 13 to V The kwinding 142 of the difi'erentialrelay 140 being included in this circuit, said relay 140 energizes, butwith no eflect. The rotary line relay 128, upon energizing, operates toclose anenergizing'c1rcuit, through the private" magnet 131, whichlatter in turn operates torelease the side 'switch from first to secondposition; For

as previously described, Q grounding the vertical line conductor33 ten.

the last digit the subscriber operates the calling device,

times and the rotary line conductor 34 once.

The vertical and rotaryline-relays 127 and .123 are 0 erated overpreviously traced cir- -.cu1ts. owever, whenthe vertical line reacircuitis closed through the rotary magnet. 130instead of through thevertical magnet .129, since the side switch wiper 136 is'now insecond-position. Each time that the rotary magnet senergized the shaftwipers .124, 125 and'126 are rotated one step at a time until the saidwipers are carried into',-engagement with .the normal conductors 1'61,162 and 163, the first two of swhich lead: to the lineterminals ofthe-de-g I sired substationj The rotary: line relay 128,

upon energizing, completes? an energizing circuit through the-privatemagnet 131 as 4 before, which latter now operates with one of tworesults, namely the release of the side switch; from first to secondposition, or the '.so-calledbusyrrelease of the connector. It

will be assumed that the former result occurs, and that the side switchposition, whereby theside switch wipers 134 passes to third and 135 are.placed in connection with the respectively. Furthermore, when the .sideswitch passes to lished for protecting "the called line. Thisnalingbutton 29, whereby the vertical line conductor 33 is grounded, andthe connector vertical line relay 1.27 and the differential relay '140becomev energized as before. It will be assumed ,that the side switchhas passed from second to third position, and

that the side switch wiper'136 is in"eng agement with athird-positioncontact point, thereby placing the vertical line relay 127 in control ofthe ringer relay 144 in the same manner in which the rotary magnet 130cameunder the control of the vertical line relay when the'sideswitch'passed from first to second position. Therefore, .when thevertical line relay presses the springs 154 and 155 into contact theringer relay 144 is energized from. ground G51 through the 156 and 157,side switch wiper 136, ringer springs 154 and private ma et 5 rin 140,through the springs 159 and 160 to the 7 gm P gs relay 144, springs 164and 165 (bearing in mind that the differential relay 140 is energized)to the battery lead 90, thence through battery 'B'to ground G. Theringer relay,

'upon-energizing, operates to bridge the terminals of the ringergenerator'E across the conductors of the desired line; A signaling r cu"rent is therefore sent from the ringer i the switch-hook, whereby theswitch-hook rises, permitting the springs 167 to disengage and thesprings 168 to engage, thereby removing the ringer-166 from across hisline and bridgin instead the transmitter and primary win ing. When theprimary winding and transmitter come across the line anenergizingcircuit is established throughboth windings of the relay 143 extendingfrom ground Gr through'the side switch wiper' 137, through the winding146 of the relay 143, through the ringer relay springs and side switchwiper 135 to the rotary normal conductor 162, rotary line conductor 169,throu h the primary win ing and transmitter to the vertical lineconductor 170, vertical normal conductor 161, shaft wiper 124 and sideswitch Wiper 134,

through the winding 145 of the relay 143,

through the springs 171 and 165 to the battery lead 90, thence throughbatteryB to, ground'G. The'relay143, upon energizing, operates to shiftthe spring 159 from the spring 160 (which latter is connected with thebattery lead 90) to the spring 17 2, which in turn is connected withground. The re- ,versal of polarity of the spring 159 sets up a circuitwhich provides the calling 'subscriber with battery current for talkingpurposes. This current may be traced from ground G through the sideswitch wiper 137, sprin s '172 and 159, through thewinding 142 o therelay 140, rotary line relay 128, conductors-158 and 34, through theprimary windi'n and transmitter of substation A to the vertical lineconductors 33 and 153, vertical line relay 127, winding 141 of thediflierential relay 140 to the battery lead 90,

thence through battery B, to ground G.- Both windings of the relay 140now carry current, but the windings are so arranged that the saidrelay-does not operatively energize. The vertical and rotary line relays127 and 128 being included in the above c1r-- cuit operatively energizeand place their springs in contact, and the release springs 173 and 174are also brought into contact,,

f but the simultaneousaction of these relays at this particular time iswithout effect, since no energizing circuits are established thereb Thetwo substations A and A being tlius provided with battery current fortalking purposes, conyersation may be carried on over circuies shown bythe heavy line I and 34, through the release 7 to the substation groundconductors in Figs. 1 and 3. The release of the central office switchingapparatus is brought about when the calling subscriber restores thereceiver 2 to the switch-hook 3,

thereby pressingthe release springs 7, 8 and 9 into engagement for amoment. The contact of the said release springs grounds the vertical androtary line conductors 33 and 34 1 simultaneously from ground G rto therelease spring 7, thence through the springs 8 and 9 to the vertical androtary line conductors. The grounding of the rotary line conductor 34produces'a short-cirouit of the rotary line relay 128 in series with thewinding 142 of the differential relay 140. The

said circuit extends from'ground Gr at'the connector to the side switchwiper 137,

springs 172 and 159, through the winding spring 160, which removes thesaid shortcircuit of the rotary line relay 128 and windits armature,

'95 spring 172 and into engagement with the ing 142 and establishes anenergizing circuit instead from the substation ground 'G? through therelease springs 7, 8 and 9 to the rdtary line conductor 34, thence tothe rotary line relay 127, as previously traced, winding 142 oftheldifl'erential relay 140, through the springs 159 and 160 to thebattery lead 90,

thence through battery B to ground G. The rotary line relay 128 nowoperates and the springs 173 and 174 come into contact, whereby anenergizing circuit is established 5 through the release magnet 132 ofthe connector F and the release relay 70 of the selector 0. However, thecurrent now in passing, as above stated, through the winding 142 aidsthe winding 141 in maintaining the springs 164 and 165 in contact. Theenergizing circuit through the release magnet 132 extends from round Gat the selector C through the si e switch wiper 50, back-release relay'70, shaft wiper 47,conductor 175, through'the release springs 173 and174, release magnet 132, springs 164 and 165 to the battery lead 90.thence through battery. B to ground G. The connector, release magnet,upon being supplied with current, energizes,-and as a result the switchshaft and sideswitch are restored tonormal condition, thus breaking theconnection between the connector switch shaft wipers 124,

125 and 126 and the normal conductors 161,

1.62 and 163. The back-release relay' 70 being in the same circuit withthe-release magnet 132 energizes simultaneously with the latter, andoperates to close the circuit through the release magnet 52 of theselector C by pressing the back-release springs 122 and 123 together.The circuit through the release magnet 69 extends from ground G throughthe springs 122 and 123, and

' through the release magnet 69 to the battery lead 90. l/Vhen theground to the line conductors 33 and 34: is interrupted, all the magnetsinvolved in the release are deenergized and all switches fullyrestored.-- If the called line #320 is busy at the time that the callingsubscriber attempts to establish con nection, the connector F isreleased by the private magnet springs 176 and 177 arebrought intocontact an energizing circuit is established through the release magnet132 from the said grounded private bank contact to the private wiper126, thence to the side switch wiper 137 (which is in second position),through the private magnet springs 176 and 177, through the winding of.the release magnet 132, springs 164 and 165 to the battery lead 90,thence through battery B to ground G. The connector switch shaft andside switch are thus released, and con nection is not established withthe called line. Now, when the calling subscriber presses the signalingbutton the vertical line relay 127 becomes energized and operates toclose the circuit through the vertical magnet 129. The vertical magnetoperates to carry the vertical shaft vertically, whereby the off-normalsprings 151and 152 engage to permit a busy-signaling current to pass tothe called subscriber in the usual way. Of course, when the subscriberhangs up his receiver after receiving the busy-signal, he grounds theline conductors 33 and 34:, as already explained, producing the releaseof the switching apparatus as formerly.

From the foregoing it will be seen that I provide a common batterysystem in which party-line subscribers uniformly call the subscribers onthe same line by a single movement of the calling dial. In other words,the special ring-back arrangement, such as shown at D, is reached by thefirst selector as a result of the numerical opera- .to which the ringback. is allotted.

tion of the dial to find the particular level After the level is found;lhowever, the selector switch, as the result of a non-numerical operation, is automatically connected with the ring back whichvisexclusively for calling between subscribers on'the same line. fTheordinary common battery connectors hav= ing ringer relays can beemployed for calling and signaling between different lines..

The said ring-back arrangement not only controls the flow of bothringing and talking currentto the substations of the party-line, 7

but also controls the trunk-release circuit extending back through thefirst-selector, in 1 Q the manner explained.

In the modification shown in common relay 35is omitted .In this systemthe ring-back arrangement is identical with that shown at D in Fig. 1,but the substation circuit is necessarily changed slightly. In thesubstations shown in Fig. 2 the ringer push button spring 32 isconnected to ground through the-springs 15 and 14 instead of through therelay 35, and the ringer circuits in Fig. 2 connect with the rotary linein the various substation instrumen-ts, and not at the relay 35 as isthecase in Fig. 1. Fig. 2 only two conductors are required between thedifierent substations on a line.

When the relay 35 is omitted-the release of opening of the rotary lineat the springs 108 and 107 of the ringer relay 85. If, however, thesignaling button at the calling substation is again pressed after thecalled subscriber has removed his receiver, the exchange apparatus mightbe prematurely released if the relay 35is not used.

What I claim as my invention is '1. The combination, in a telephonesystem, of a party-line, a plurality of subscribers stations on saidline, a ringing apparatus, automatic selectors having one contact levelthereof adapted for automatically extending said line into connectionwith said ringing apparatus, and having other levels thereof adaptedforservice in'calling subscribers on other lines, subscribers trans-Knitters connected to receive current for talking purposes from theexchange or central station and means for transmitting ringing currentfrom said ringing apparatus via said selectors to said line.

2. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on said line, a special party-lineringing apparatus used only when one subscriber is calling another uponthe Fig. 2 the With the apparatus shown in same line, automatic meansfor connecting said line directly with said ringing apparatus to enableone subscriber to call another on the same line, subscriberstransmitters connected to receive current for talking purposes from theexchange or central station, and means for transmitting ringingcurrent/from said ringing apparatus via said automatic means.

3. The combination, in a telephone system, of a party-line, a pluralityof subscribers"stations located on said line, other lines, meansincluding automatic connectors for calling from one line to another,means including a special ringing apparatus independent of saidconnectors, adapted for enabling one party-line subscriber to callanother on the same line, without using said connectors, subscriberstransmitters connected to receive current for talking purposes -from theexchange or central station, said first means comprising a switch forex-. tending connection to said ringing apparatus and means fortransmitting ringing current from said ringing apparatus via said switchto the said line. L. The combination, in a telephone system, of asubscribers telephone line, automatic means for trunking calling linesinto connection with called lines, a plurality of subscribers stationson one or more of said lines, an automatic ringing apparatus exclusivelyfor use between calling and called subscribers on the same line,subscribers transmitters connected to receive current for talkingpurposes from the exchange or central station, said-automatic meanscomprising a switch for extending connection to said ringing apparatus,and means for transmitting ringing-current from said ringing apparatusvia said switch to the said line.

'5. The combination in a telephone 'system, of a party-line, a pluralityof subscribers stations on said line, a rotary calling dial for eachsubscribers station, adapted to come to rest after operation thereof foreach digit of the called number, means including automatic switcheswhereby one subscribers line can be connected with another line,automatic means by which subscribers on the same line uniformly calleach other by a, single movement of the dial, and subscriberstransmitters connected to receive current for talking purposes from theexchange or central station.

6.-The combination, in a telephone sys- I tem, of a party-line, aplurality of subscribers stations located on said line, other lines, acalling dial for each subscribers station, means necessitating aplurality of movements of the dial when a party-line subscriber calls asubscriber of some other line,

automatic means by which subscribers on the same line uniformly calleach other by a single movement of the dial, and subscriberstransmitters connected to receive current for talking purposes from theexchange or central station.

7. The combination, in a telephone system, of means for signalingbetween subscribers on the same line, said means comprising a pair ofline relays, a ringer relay governed by one of said line, relays, anautomatic switch and a release circuit therefor controlled by theenergizing of the linerelays simultaneously, subscribers transmittersconnected to receive current for talking purposes from the exchange or.central station, means for extending said line to said signaling means,and means for transmitting ringing current, from said signaling meansvia said connecting means to said line.

8. The combination, in a telephone system, of means for. signalingbetween subscribers on the same line, said means comprising a pair ofline relays, a ringer relay governed by one of said relays, a source ofringing current adapted to be connected for ringing said line relays,subscribers transmitters connected to receive current for talkingpurposes from the exchange or central station, means for extending saidline to said signaling means, and means for transmitting ringing currentfrom said signaling means via said connecting means to said line.

9. The combination, in a telephone system, of means for signalingbetween subscribers on the same line, said means comprising a pair ofline relays, a battery to one pole of which the windings of said relaysare connected in multiple, a ringer mechanism governed by one of saidline relays, an automatic switch and a trunk-release circuit thereforcontrolledjby the energizing of the line relays simultaneously,subscribers transmitters connected to receive current for talkingpurposes from the exchange or central station, means for extending saidline to said signaling means, and means for transmitting ringing currentfrom said signaling means via said connecting means to said line.

10. The combination, in a telephone system, ofmeans forsignaling betweensubscribers on the same line, said/means comprising a pair of linerelays, a batte to one pole of which the windings of sai relays areconnected in multiple, a ringer mechanism governed by one of said linerelays, an automatic switch and a trunk-release circuit thereforcontrolled by the energizing of the line relays simultaneously, meansfor extending connection to said signaling aim for bridging said batteryacross the line cir cuit to supply current for talking purposes tocalling and called stations on the same line. 7 I V 11. The combination,in a telephone system, of a party-line, a plurality of subscribersstations on said line, a ringing apparatus, automatic selectors havingone level thereof adapted for automatically extending said line intoconnection with said ringing apparatus and having other levels thereofadapted for other service, ringers at said stations, each ringerconnected via a condenser-to one-side of the line and switch hookcontrolled means 'for disconnecting each ringer separately from theother side of said line, and means for transmitting ringing currentfromsaid ringing apparatus to said line via said selectors.

12. The combination, in a telephone system', of a party-line, aplurality of subscribers stations located on said line, a ringingapparatus, au'tomaticmeans for extending said line directly to saidringing apparatus to enable one subscriber to call another on the sameline, ringers at said stations, each ringer connected via a condenser toone side offthe line and switch hook controlled means for disconnectingeach ringer separately from the other side of said line, and means fortransmitting ringing current from said ringing apparatusto said line viasaid automatic means. v

1.3. The combination, in a telephone system, of a party-line, aplurality of subscriber's stations located on said line, other lines,means including automatic connectors for calling from one line toanother, a special ringing apparatus independent of said connectors andadapted for enabling one partyline subscriber to call another on thesame line, ringers in said stations, each ringer connected via acondenser to one side of the line and switch hook controlled means fordisconnecting each'ringer separately from the other side of said line,and means for extending said line to said ringing apparatus, wherebysaid apparatus may transmit ringing current to the calling line via saidlast denser to one side of the line and switch hook controlled means fordisconnect-ing each ringer separately from the other side of the line.

tem, of a subscribers telephone line,,auto-' V matic means for trunkingcalling lines into connection withccalled lines, a plurality ofsubscribers stations on one or more of said lines, an automatic ringingapparatus exclusively for use between calling and called sub scribers onthe same line, means for extending connection from one of saidlast linesto said automatic ringing apparatus, and means for transmittingsignaling current from said ringing apparatus via said extending meansto said last line, ringersat said stations, each ringer connected via acondenser to one side of the line and switch hook controlled means fordisconnecting each ringer separately from the other side of said line."

16.-The combination, in'a telephone system, of a party-line, a pluralityof subscribers stations on said line, a calling. dial for eachsubscribers station, automatic means by which subscribers on the sameline uni- V formly call each other by a single movement of the dial,ringers at said stations, each ringer connected via a condenser to oneside of the line and switch hook controlled means "for disconnectingeach ringer separatel from the other-side of said line. a .1

17. The combination, in a telephone system, of a party-line, a pluralityofsubscribers stations located on said line, other lines, a calling dialfor each subscribers station, means necessitating a 'plurality ofmovements of the dial when a party-line subscriber calls a subscriberof'some other line,

automatic means by which subscriber's on the same line uniformly calleach other by a single moveinent of the dial, ringers at said stations,each ringer connected via a condenser to one side of the line and switchhook controlled means for disconnecting each ringer separately from theother side of said line. 0

18. The combination, in a telephone system, of a special ring-backarrangement, comprising a pair of line relays, means for reaching thesaid arrangement, a ringer re: lay governed by one of said line relaystosend ringing current back over "said means for signaling betweensubscribers on the same line, a release circuit for said meanscontrolled by the energizing of the line re-' lays simultaneously,ringers at said stations, each ringer connected via a condenser to oneside of the line and switch hook controlled means for disconnecting eachringer separately from the other side of said line.

19. The combination, in a telephone system, I

of a device for signaling between subscribers stations on the same line,said device com- ,prising a pair of line relays, means including anautomatic switch for reaching said device, abattery to one pole of whichthe winding of said relays are connected in multiple, a ringer mechanismgoverned by one of said line relays to send ringing current back oversaid means for signaling between subscribers on the same line, atrunkrelease circuit for said switch controlled by the energizing of theline relays simultaneously, ringers at said stations, each ringerconnected via a condenser to one side of the line and switch hookcontrolled means for disconnecting each ringer separately from the otherside of the line. 20. The combination, in atelephone system, of aparty-line, a plurality of subscribers stations located on said line, anautomatic switch controllable from anyone of said stations, trunkshaving terminals in said switch, one or more of said terminalsappropriated exclusively for calling between subscribers on the sameline, means for controlling said switch to extend a connection oven saidtrunks for signaling back over said switch, ringers at said stations,each ringer connected via a condenser to one side of said line andswitch hook controlled means 'for disconnecting each ringer separatelyfromthe other side of said line, a test circuit for oneof said trunks,and means in the automatic switch controlled over said test circuit forcausing the switch to move away from the terminals of one of said' trunkterminals, one level of said bank being appropriated exclusively forcalling between subscribers on the same line, means for controlling saidswitch to extend a connection over sai said switch, ringers at saidstations, each ringer connected via a condenser to one side -of saidline and switch hook controlled line.

means for disconnecting each rin er separately from the other side ofsaid ine, test circuits for said trunks, and means in the automaticswitch controlled over said test circuits for causing the switch to moveaway from the terminals of one of said trunks. I

22. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on'said line, a ringing apparatus,automatic means for connecting said line directly with said ringingapparatus to enable one subscriber to call another on the same line, anda relay for opening one side of the party-line when one sub-' scriberthereon rings another on the same .23. The combination, in a. telephonesystem, of a party-line, a plurality of subscribers stations located onsaid line, other lines, means including automatic connectors for callingfrom one line to another, a special'ringing apparatus independent ofsaid connectors and adapted for enabling one trunks for signaling backover,

party-line subscriber to call another on the same line, and a relay foropening one side of the party-line when one subscriber thereon ringsanother on the same line.

24. Thecombination, in a telephone system, of a party-line, a pluralityof subtem, of a subscribers'telephone line, auto-.

matic means for trunking calling lines into connection with calledlines, a plurality of subscribers stations on one or more of said lines,an automatic ringing apparatus exclusively for use between calling andcalled subscribers on the same line, and a relay for opening one side ofthe party-line when one fubscriber thereon rings another on the same 726. The combination, in a telephone system, of a party-line, a pluralityof subscribers stationson said line, a calling dial for each subscrlbersstation, automatic means by which subscribers on the same line uniformlycall each other by a single movement of the dial, and a'relay foropening one side of the party-line when one subscriber thereon ringsanother on the sameline. Q, l

27. The combination, in a telephone system, of v a party-line, aplurality of subscribers stations located on said line, other lines, acalling dial for each subscribers station, means necessitating aplurality of movements of the dial when a party-line subscriber calls asubscriber of some other line, automatic means by which subscribers onthe same line uniformly call each other by a single movement of thedial, and a relay for opening one side of the party-line when onesubscriber thereonrings another on the same line.

28. The combination, in a telephone sys tem, of a special ring-backarrangement for signaling between subscribers on the same line,comprising a pair of line relays, a ringer relay governed by one of saidline relays, an automatic switch and a release circuit thereforcontrolled by the energizing of the line relays simultaneously, and arelay for opening one side of the party-line when one subscriber thereonrings another on the same line. .1

29. The combination, in a telephone system, of, a special ring-backarrangement for signaling between subscribers on the same line,comprising a pair of line relays, a ringer relay governed by one of saidrelays, a source of ringing current adapted to be connected for ringingby the energizing of the ringer relay, an automatic switch and circuittherefor controlled by the simultaneous energizing of said line relaysfor controlling the switch, and a relay for opening one side of theparty-line when one subscriber thereon rings another on the same line.

30. The combination, in a telephone system, of a special ring-backarrangement for signaling between subscribers on the same line,comprising a pair of line relays, a battery to one pole of which thewindings of said relays are connected in multiple, a ringer mechanismgoverned by one of said line relays, an automatic switch and atrunkrelease circuit therefor controlled by the energizing of the linerelays simultaneously, and a relay for opening one side of theparty-line when one subscriber thereon rings another on the same line.

31. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on said line, an automatic switchcontrollable from any one of said stations, trunks having terminals insaid switch, one or more of said terminals appropriated exclusively forcalling between subscribers on the same line, and a relay for openingone side of the party-line when one subscriber thereon rings another onthe same line.

32. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on said line, an automatic switchprovided with a bank of trunk terminals, one level of said bank beingappropriated exclusively for calling between subscribers on the sameline, and a relay for opening one side of the party-line when onesubscriber thereon ringsanother on the same line.

33. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations on said line, a ringing apparatus, automaticselectors having one level thereof adapted for automatically extendingsaid linetinto connection with said ringing apparatus and having otherlevels thereof adapted for other service, and a relay adapted foropening one side of the party-line and provided with means forshort-circuiting a portion of its own resistance when energized bycurrent from the central station.

34. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on said line, a ringing apparatus,automatic means for connecting said line directly with said ringingapparatus to enable one subscriber to call another on the same line, anda relay adapted for opening one side of the party-line and provided withmeans for short-circuiting a portion of its own resistance whenenergized by current from the central station.

35. The combination, in a telephone system, of a party-line, a pluralityof sub scribers stations located on said line, other lines, meansincluding automatic connectors for calling from one line to another, aspecial ringing apparatus independent of said connectors and adapted forenabling one partyline subscriber to call another on the same line, anda relay adapted for opening one side of the party-line and provided withmeans for short-circuiting 'a portion of its own resistance whenenergized by current from the central station.

36. The combination, in a telephone sys tem, of a party-line, aplurality of subscribers stations located on said line, other lines,means necessitatinga calling of the called subscribers number. incalling from one line to another, means for enabling one party-linesubscriber to signal another subscriber on the same line responsive toimpulses differing in number from those corresponding to the number ofthe latter, and a relay adapted for opening one side of the party-lineand provided with means for' short-circuiting a portion of its ownresistance when energized by current from the central station. p

37. The combination, in a telephone system, of a subscriberstelephone'line, automatic means for trunking calling lines intoconnection with called lines, a'plurality of subscribers stations on oneor more of said lines, an automatic ringing apparatus exclusively foruse between calling and called subscribers on the same line, and a relayadapted for opening one side of the partyline and provided with meansfor short-circuiting a portion of its own resistance-when energized bycurrent from the central station.

38. The combination, in a telephone sys tem, of a party-line, aplurality of subscribers stations on said line, a calling dial for eachsubscriberfs station, automatic means by which subscribers on the sameline uniformly call each other by a single movement of the dial, and arelay adapted for opening one side of the party-line and pro-- videdwith means for short-circuiting 'aportion or its own resistance whenenergized by current from the central station. 7

39. The combination, in a telephone system, of a party-line, a pluralityof sub scribers stations located on said line, other lines, a callingdial for each subscribers station, means necessitating a plurality ofmovements of the dial when a party-line subscriber calls a subscriber ofsome other line,

automatic means by which subscribers on I 45 .means for short-circuitinga portion of its adapted for opening one side of the party-' w energizedby current from the central station.

4:0. The combination, in a telephone sys tem, of a special ring-backarrangement for signaling between subscribers on the same line,comprising a pair of line relays, a ringer relay governed by one of saidline relays, an automatic switch and a release circuit thereforcontrolled by the energizing of the line relays simultaneously, and a1'6? lay adapted for opening one side of the party;line and providedwith means for short-circuiting a portion of its own-resistance Whenenergized by current from the central station.

tem, of a special ring-back arrangement for signaling betweensubscribers on the same line, comprlslng a pair oflline relays, a.

ringer relay governed by one of said relays, a source of ringing currentadapted to be connected for ringing by the energizing of the ringerrelay, an automatic switch and a circuit therefor controlled by thesimultaneous energizing of said line relays for controlling the switch,and a relay adapted for opening one side of the party-line and providedwith means for short-circuiting a portion of its own resistance whenenergized by current from the central station.

42. The combination, in a telephone system, of a special ring-backarrangement for signaling between subscribers on the same line,comprising a pair'of line relays, a battery to'one pole of which thewindings of said relays are connected in multiple, a ringer mechanismgoverned by one of said line relays, and automatic. switch and atrunk-release circuit therefor controlled by tion? the energizing of theline relays; simultaneously, and a relay adapted for opening one side ofthe party-line and provided with own resistance when energized bycurrent from the central station./

43. The combination, in a telephone system, of a party-line, a pluralityof subscribers stations located on said line, an automaticswitchcontrollable from any one of I said stations, trunks having terminals in'said switch, one or more of said terminals 7 appropriated exclusivelyfor calling between I subscribers on the same line, and a relay adaptedfor opening one side of the party- 'line and provided with means forshort-circuiting aportion of its ownresistance when energized by currentfrom the central sta- 44.- The combination, in a telephone system, of aparty-line, a plurality of SlJbSCI'lb- ,ers stations located on saidline, an automatic switch provided W1th a bank of'trunk only at acertain level for ringing back over said switch, a common battery fortalking purposes, and means for controlling the operation of saidswitch.

46. In a telephone system, a party-line, means including an automaticswitch for calling'backon said line, means for releas- 41. Thecombination, in a telephone sysa subscriber, and a relay adapted to beenergized during signaling to open the opposite side of said line toprevent the release of said switch.

48. In a telephone system, a line, a 111- rality ofsubscribers stationson said ine, means for grounding one side of said line to signal asubscriber, a relay adapted to be energized during signaling, and meanscontrolled by said relay for opening the oppo- 1 site side of, said lineduring the signaling operation to enable one subscriber on said line tosignal another subscriber thereon. i

49. In a telephone system, a subscribers.

line, means for grounding one sideof said 11 0 line to signal thesubscriber thereon, a relay having a pair of energizing windings adaptedto1be energized during-signaling, and means controlled by the operation/of said relay for opening the opposite side of said 115 line and forshort-circuiting one of the? windings of said relay. I

50. The combination, in a telephone system, of a special ringingarrangement comprising a pair of line relays, means comprising aprogressively movable switch for reaching the said arrangement, aringing relay governed by one of said line relays to send ringingcurrent back over said means for signaling between subscribers stationson the same line, a circuit for said means controlled by thesimultaneous energizing of said line relays for controlling the switch,

ringers at said stations, each ringer connected via a condenser to oneside of the l1ne and switch hook controlled means for disconnecting eachringer separately from the other side of said line. I

V 51. In a telephone system, the combina-. tion of a line, a pluralityof subscribers stations on said line, a ringing apparatus, progressivelymovable central ofiice equipment for said line for establishingconnection with said ringing apparatus, said ringing apparatuscomprising means for-sending ringing current only to the calling line, acentral battery, subscribers transmitters one for each station,said'transmitters connected to receive current for talking purposes fromsaid central battery.

52. In a telephone system, the-combina: tion of a line, a plurality ofsubscribers stations on said line, a ringing a paratus, progressivelymovable central 0 cc equipment for said line for establishing connectionwith said ringing apparatus, said rmgmg apparatus being ready to sendringing current only to the calling line as soon as it is seized by thesaid switch, and subscribers said-line, and subscribers transmittersconnected to receive current for talking purposes from the exchange orcentral stat on.

54:. In a telephone-system, the combination of a line, a plurality ofsubscribers stations on said line, a source of ringing current,automatic means for extending a non-inductive connection from said lineto said source to enable one subscriber to signal another subscriber onthe same line by transmitting signaling current from sald source viasaid automatic means to said line, and

subscribers transmitters connected to receive current for, talkingpurposes from the exchange or central station, a test circuit for saidline and means controlled by said automatic means for applying apotential over said test circuit to guard the line against seizure,

55. In a telephone system, the combination of a line, a plurality ofsubscribers stations on said line, a ringing apparatus, progressivelymovable central ofice equipment for said line for establishing connection with said ringing apparatus, said ring-- ing apparatus comprisingmeans for sending ringing current to the calling line, a centralbattery, subscribers transmitters, one for each station, saidtransmitters connected to receive current for talking purposes from saidcentral battery, a test circuit for said line, and means controlled bysaid equipment for applying a potential over said test circuit to guardthe line against seizure.

56. In a telephone system, the combination of'a line, a plurality ofsubscribers stations on said line, a ringing apparatus,

progressively movable central office equipment for said line forestablishing connection with said ringing apparatus, said apparatusbeingready to send ringing current to the calling line as soon as itisseized by the said switch, subscribers transmitters connected to receivecurrent for talking puroses from the central station, a test circuit orsaid line, and means controlled by said equipment for applying apotential over seizure.

57. In a telephone system, a subscribers' line, an automatic switchassociated with said line, said switch provided with means forsignaling, means for grounding one side of said line to signal thesubscriber, and means for opening the other side ofsaid line between thesubstation and the central ofiice for preventing the switch operating torensaid test circuit to guard the "line against der the means forsignaling inoperative dur:

ing said signaling.

58; Ihe combination in a telephone system of a line, a plurality ofsubscribers stations for said line, a transmitter for each station, asignal for each station connected to the-line,- an automatic switchassociated with the line, means for controlling said switch from'any oneof said stations, lines having terminals accessible to said switch,

means controlled over said lines for operating anyone of said signals,means for connecting the transmitter of any signaled station to theline, a centralbattery for supplyin current to any transmitter over saidline or talking purposes, a test circuit for said line terminating insaid: switch, said switch having means controlled over said circuit forcausing the switch to move away from the terminals of said line.

59. 'The'combination, in a telephonevsystem, of a line, a plurality ofsubscribers stations for said line, a transmitter foreach station, asignal for each station connected to the line, an automatic switchassociated with the line, means for controlling said switch from any oneof said stations, said switch provided with a bank of terminals,

certain of said terminals being used for calling between stations on thesame line, means controlled over said'trunk lines for operating any oneof said signals, means for con trunk-lines terminating in saidterminals, I

necting the transmitter of any signaled sta- 1 tion to the line, acentral battery for supplying current to said transmitter over said linefor talking purposes, a test circuit for said line terminating in saidswitch, said switch having means controlled over said I test circuit forcausing the switch to move away from the terminals of said line.

60. In a telephone system, the combination of a plurality of lines, aplurality of stations on each'line, an auxiliary line, terminals forsaid auxiliary line, ringing apparatus controlled over said auxiliaryline, progressively movable switching equipment for said lines havingaccess to said terminals for establishing connections with saidapparatus whereby said apparatus may be controlled over saidlines, saidapparatus comprising means for sending ringing current to any one ofsaid lines only over said terminals, and a central battery for supplyingcurrent to said lines for talking purposes.

61. In a telephone system, a two conductor line and a signal connectedthereto, a two conductor trunk line, a switch controllable'over saidfirst line for connecting the two lines, a pair of line relays, a doublewound relay and a grounded battery all in series with the two conductorsof said trunk line,. said relays normally inoperative, a source ofsignaling current, means under the control of one of said line relaysfor connecting said source to said trunk line to operate said signal,means for releasing said switch and a circuit for said means controlledjointly by said line relays, means controlled by said double wound relayfor shifting one of its windings from the grounded to the ungroundedpole of said battery, and means for grounding one or both conductors ofsaid line whereby the associated signal may be operated or the saidswitch released, substantially as described.

62. In a telephone system, the combination of a line, a plurality ofsubscribers 40 stations on said line, a ringing device including asource of ringing current, automatic means for extending connection fromsaid line to said source of current to enable one subscriber to signalanother subscriber on the same line after said automatic means isoperated by transmitting signaling current from said source via saidautomatic means to said line, subscribers transmitters connected toreceive current for talking p'urposes from the exchange or centralstation, and means for connecting said source of current across theline.

Signed by me at Chicago, Cook county, Illinois, this 14th day ofSeptember, 1907.

FRITZ LUBBERGER.

